• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.284-294
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• 2008

In this paper, we describe an implementation of small mobile robot that can be used at research and application of mobile sensor networking. This robot that will constitute the sensor network, as a platform of multi-robot system for each to be used as sensor node, has to satisfy restrictions in many aspects in order to perform sensing, communication protocol, and application algorithms. First, the platform must be designed with a robust structure and low power consumption since its maintenance after deployment is difficult. Second, it must have flexibility and modularity to be used effectively in any structure so that it can be used in various applications. Third, it must support the technique of wireless network for ubiquitous computing environment. At last, to let many nodes be scattered, it must be cost-effective and small. Considering the above restrictions of the mobile platform for sensor network, we designed and implemented robots control the current of actuator by using additional circuit for power efficiency. And we chose MSP430 as MCU, CC2420 as RF transceiver, and etc, that have the strength in the aspect of power. For flexibility and modularity, the platform has expansion ports. The results of experiments are described to show that this robot can act as sensor node by RF communication process with Zigbee standard protocol, execute the navigation process with simple obstacle avoidance and the moving action with RSSI(Received Signal Strength Indicator), operate at low-power, and be made with approx. $100.

• Journal of Ocean Engineering and Technology
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• v.19 no.5 s.66
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• pp.16-25
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• 2005

The effect of vertical riser support system on the dynamic behaviour of a classical spar platform is investigated. Spar platform generally uses buoyancy-can riser support system, but as water depth gets deeper the alternative riser support system is required due to safety and cost issues. The alternative riser support system is to hang risers off the spar platform using pneumatic cylinders rather than the buoyancy-can. The existing numerical model for hull/mooring/riser coupled dynamics analysis treats riser as an elastic rod truncated at the keel (truncated riser model), thus, in this model, the effect of riser support system can not be modeled correctly. Due to this reason, the truncated riser model tends to overestimate the spar pitch and heave motion. To evaluate more realistic global spar motion, mechanical coupling among risers, guide frames and support cylinders inside of spar moon-pool should be modeled. In the newly developed model, the risers are extended through the moon-pool by using nonlinear finite element methods with realistic boundary condition at multiple guide frames. In the simulation, the vertical tension from pneumatic cylinders is modeled by using ideal-gas equation and the vertical tension from buoyancy-cans is modeled as constant top tension. The different dynamic characteristics between buoyancy-can riser support system and pneumatic riser support system are extensively studied. The alternative riser support system tends to increase spar heave motion and needs damper system to reduce the spar heave motion.

• The Transactions of the Korea Information Processing Society
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• v.6 no.9
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• pp.2493-2503
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• 1999

The TMN that appears to operate the various communication networks generally and efficiently is developed under the different platform environment such as the different hardware and the different operating system. One of the main problems is that all the agents of the TMN system must be duplicated and maintain the software and the data blocks that perform the identical function. Therefore, the multi-platform cannot be supported in the development of the TMN agent. In order to overcome these problems, the Farming methodology that is based on the Farmer model has been suggested. With the Farming methodology, the software and the data components which are duplicated and stored in each distributed object are saved in the platform independent class repository (PICR) by converting into the format of the independent componentware in the platform, so that the componentwares that are essential for the execution can be loaded and used statically or dynamically from PICR as described in the framework of each distributed object. The distributed TMN agent of the personal communication network is designed and developed by using the Farmer model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.2
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• pp.247-268
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• 2011

Due to the application-specific nature of wireless sensor networks, the sensitivity to such a requirement as data reporting interval varies according to the type of application. Such considerations require an application-specific, parameter tuning paradigm allowing us to maximize energy conservation prolonging the operational network lifetime. In this paper, we propose a reporting interval adaptive, sensor control platform for energy-saving data gathering in wireless sensor networks. The ultimate goal is to extend the network lifetime by providing sensors with high adaptability to application-dependent or time-varying, reporting interval requirements. The proposed sensor control platform is based upon a two phase clustering (TPC) scheme which constructs two types of links within each cluster - namely, direct link and relay link. The direct links are used for control and time-critical, sensed data forwarding while the relay links are used only for multi-hop data reporting. Sensors opportunistically use the energy-saving relay link depending on the user reporting, interval constraint. We present factors that should be considered in deciding the total number of relay links and how sensors are scheduled for sensed data forwarding within a cluster for a given reporting interval and link quality. Simulation and implementation studies demonstrate that the proposed sensor control platform can help individual sensors save a significant amount of energy in reporting data, particularly in dense sensor networks. Such saving can be realized by the adaptability of the sensor to the reporting interval requirements.

• Composites Research
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• v.36 no.2
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• pp.108-116
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• 2023

In this paper, kinematic design and multi-body dynamics analysis were conducted to develop a small manipulator platform for automating the maintenance of structures made of composite materials. To design manipulator kinematically, the existing composite repair process was considered. The 3D design was conducted after selecting the basic specifications of manipulator and end-effecter in consideration of the patch lamination process for repair. Then, variables necessary for simulation and control were generated in MATLAB through inverse kinematic analysis. To evaluate the structural stability of platform, multibody dynamics analysis was conducted using Altair Inspire and Optistruct. Based on the simulation conducted in Inspire, multibody dynamics analysis was conducted in Optistruct, and structural stability was verified through the results of maximum displacement and Von-Mises stress over time. To verify the design, manufacturing and controlling of platform were conducted and compared with the simulation. It was confirmed that the actual repair process path and the simulation showed a good agreement.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.561-571
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• 2021

As the game industry grows, the companies are promoting price discounts to increase game sales and profits. Consumers generally feel guilt when they are purchasing games. Previous studies argue that consumers feel less guilty and justify their consumption more easily when they are purchasing hedonic products at discounted price. In this study, we argue that there are different types of games; multi-game where consumers socialize each other and single games not supporting socializing. In the multi-game, consumers make social relationship which can provide substantial benefits. Since multi-games are promoting consumers' socializing expected to have those benefits. Although most of game consumptions bring a sense of guilty feeling, purchasing multi-game may not cause guilt much because the benefits of socializing justify the consumption. To support my hypothesis, we collect the data from global game platform Steam to analyze the relationship between price promotion and number of consumers. As a result, price promotion has significantly different relationship between multi-and single game. The results of this study suggest several managerial implications.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.119-120
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• 2007

• Journal of Sensor Science and Technology
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• v.26 no.1
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• pp.35-38
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• 2017

A thermally responsive hydrogel has reversibility with temperature during swelling. Here, we proposed origami inspired temperature sensor by using multi-layered hydrogel film. The formation of patterned stripes on microscale film drives bending to an angle that can be controlled linearly. Although temperature range was not wide, measured sensitivity of sensors has high resolution and accuracy. It providing a powerful platform for the design of sensitive sensors and that easily adapt other type of sensors in microscale.

• Broadcasting and Media Magazine
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• v.22 no.4
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• pp.11-17
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• 2017

본 고에서는 멀티 응용 데이터 플랫폼으로 진화하고 있는 하둡(Hadoop) 2.0의 주요 특징과 관련된 다양한 데이터 처리 프레임워크들에 대해서 기술하고자 한다. 기존의 맵리듀스(MapReduce) 기반의 배치 처리(Batch Processing)에 최적화되어 있던 하둡 1.0과는 달리, YARN의 등장과 함께 시작된 하둡 2.0 플랫폼은 다양한 형태의 데이터 처리 워크플로우들(Batch, Interactive, Streaming 등)을 지원할 수 있는 기능을 제공하고 있다. 또한, 최근에는 고성능컴퓨팅 분야에서 주로 활용되던 기술들도 하둡 2.0 플랫폼에서 지원되고 있다. 마지막으로 YARN 어플리케이션 개발 사례로서 본 연구팀에서 개발 중에 있는 Many-Task Computing (MTC) 응용을 위한 신규 데이터 처리 프레임워크를 소개한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.922-924
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• 2002

현재 IC카드는 통신, 금융, 교통 등의 여러 응용 서비스에서 널리 사용되고 있는데, 계속적인 하드웨어 기술의 발전으로 인한 메모리 증가, CPU 성능 향상과, 통합된 정보 가전을 위한 다양한 형태의 네트워크 연결 인터페이스 구축 노력이 다중 응용 프로그램(Multi-Application) 사용 요구 및 개방형 운영체제(Open-platform Operating System)와 맞물려 도약적인 기술 발전을 이루고 있다. 본 고에서는 널리 사용되고 있으며 향후 시장성이 가장 클 것으로 예측되는 자바 카드 플랫폼 탑재 IC카드의 기술 현황을 H/W 및 S/W측면에서 살펴보고, 자바 카드 기술의 발전 동향을 조망하고자 한다.